Beat butter at medium speed with an electric mixer until creamy; gradually add brown sugar, beating until light and fluffy. Gradually add flour, beating at low speed until smooth. Cover and chill 30 minutes.
Roll dough to 1/4-inch thickness on a lightly floured surface. Cut with a 2-inch tree-shaped cutter; place 1 inch apart on lightly greased baking sheets. Sprinkle with sparkling sugar.
Bake at 375° for 10 to 12 minutes or until edges are golden; cool on baking sheets on wire racks 5 minutes. Remove to wire racks to cool completely.